In message ,
Bob E. writes
75-ohm RG-6 coax: quad shield differs from "standard" RG-6 in that the
dielectric is reduced in diameter to accomodate the extra shielding.

How does this affect the performance? I'm looking at 1 GHz (HDTV use).

Thanks.

I note that there have been a some replies, but none seem to make much
attempt at answering your question.

RG6Q is used extensively in the UK cable TV industry as 'drop' cable -
ie from the taps in the street cabinet to the home. It is used to
provide a high degree of immunity from ingress of interfering signals -
especially those at the lower frequencies (in the reverse path part of
the spectrum - typically between 5 and 65MHz). RG6 is not a particularly
low-loss cable, and for long drop runs, RG11 is sometimes used.

As for the attenuation differences between RG6 and RG6Q, I've done a bit
of Googling, and I can't see anything which is immediately pointed out.
Even on this site
http://www.ehow.com/list_7605813_difference-between-rg6-rg6q.html
all it says is that "RG-6 and RG-6Q share nearly the exact same outer
dimensions and have similar flexibility. RG-6Q is slightly stiffer due
to the increased amount of inner shielding".

I suspect that even if the diameter of the RG6Q dielectric is slightly
less (something which I've never really noticed) - requiring a slightly
thinner inner conductor in order to preserve the Zo - the increase of
attenuation won't be very much. However, I'm sure that a bit more
intensive Googling on RG6 physical and electrical specs will reveal the
true answer!
--
Ian

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